1.
 Usually the term refers to the six
classical simple machines which
were defined by scientists.

2.
The Lever

3.
a rigid bar that is free to turn about a
fixed point called the fulcrum
Every Lever has three (3) parts:
1. Resistance Force, Input Force or
Load, What you are trying to move or
lift.
2. Effort Force or Output Force - The
work done on the Lever.
3. Fulcrum – A fixed pivot point.

4.
THE PULLY

5.
• A pulley changes the direction of the
force:
– Instead of lifting up, you can pull down
using your body weigh against the load
(what is being lifted)
• A pulley gains nothing in
force, distance or speed

6.
a wheel that turns around an
axle
• A pulley is a grooved wheel that turns
around an axle (fulcrum), and a rope
or a chain is used in the grove to lift
heavy objects.
• A pulley may be fixed, moveable, or
used in combination.

7.
• A moveable pulley
acts
– the load is between
the fulcrum and the
effort

8.
• A compound pulley
is a system of
movable pulleys.
• Mechanical
advantage can be
increased by using
more than one
pulley.

9.
The Inclined Plane

10.
a sloping surface that does not
move
• An inclined plane provides for NOT
Less work but less effort.
• The trade off is greater distance to
travel.

11.
The Inclined Plane

12.
The Screw

13.
The Screw
an inclined plane wrapped around a
central cylinder
• A Screw has two (2) parts:
– The Body – Cylinder Post
– The Thread – Inclined Plane wrapped
around the cylinder.

14.
The Screw
• Functions of the screw
– To fasten things – the standard screw or
nuts & bolts.
– Drill bits are screws used to make holes.
– A jackscrew is used to lift heavy objects;
car jack.

15.
The Screw
• When you turn a screw:
– The input force is changed by the
threads into an output force.
– The output force pulls the screw into the
materials.
– Friction between the threads & the
material holds the screw in place.

16.
The Wedge
an inclined plane that tapers to a
sharp edge
• The wedge used to increase force.
• The material remains in place while he
wedge moves through it.
• A wedge changes the direction of the
input force.

17.
The Wedge
• Wedges can be forced between two
things to hold them tightly
together, like nails or a doorstop.
• Wedges can be used to split, cut or
fasten.

18.
The Wheel & Axle

19.
The Wheel & Axle
a wheel connected to a rigid
pole
• The Wheel & axle is a modified lever:
– The center of the axle acts as a fulcrum –
making the wheel a lever that rotates
around in a circle.